Defect detection and sizing in metals using ultrasound

Abstract

The factors which influence the ability of ultrasonic techniques to detect and size defects in metals are considered. To do this the theory of the interaction between defects and elastic waves must be introduced but this is presented in a largely descriptive manner with suitable references to the detailed derivations. It is shown that the basic physics of the interaction process places limits on the detectability of defects using ultrasonic techniques. In this way it is also possible to identify the important sources of variability in response. A number of current inspection techniques are then considered and, in the light of the theoretical descriptions, their strengths and weaknesses discussed. Finally, with a view to future studies, some of the more recently developed testing and sizing techniques are considered in the same manner.